PLK1 and T-cell acute lymphoblastic leukemia: Overexpression of PLK1 has been identified in samples taken from patients with lung, breast, colon, pancreas, prostate and ovary tumors, and approximately 6% of all primary human tumors harbor mutations in FBXW7α, with the greatest mutation rates found in cholangio-carcinoma and T-cell acute lymphoblastic leukemia [1, 44].